Mobile communication networks are evolving continuously. The Universal Mobile Telecommunications System (UMTS) is a 3GPP-defined third-generation technical standard for radio communication networks. With a structure similar to the second-generation mobile communication systems, the UMTS includes a Universal Terrestrial Radio Access Network (UTRAN), a Core Network (CN), and a User Equipment (UE). The UTRAN is a terrestrial radio access network and configured to handle all radio functions and operations. The UTRAN includes one or more Radio Network System (RNS), each of which includes a Radio Network Controller (RNC) and one or more NodeB. The Core Network is configured to handle all voice calls and data interaction of the UMTS and perform switching and routing functions with external. The Core Network further includes a Packet-Switched (PS) domain and a Circuit-Switched (CS) domain. The PS domain includes a Serving General Packet Radio Service (GPRS) Support Node (SGSN), a Gateway GPRS Supporting Node (GGSN), and a Home Location Register (HLR).
Currently, 3GPP is researching low-cost evolving network architecture that the time delay may be reduced, the user data rates may be increased and the system capacity and coverage may be improved, and the evolving network architecture may support future mobile network applications, including Long-Term Evolution (LTE) of access network and System Architecture Evolution (SAE). For example, LTE access network generally may be Evolving Universal Terrestrial Radio Access Network (E-UTRAN).
FIG. 1 is a simplified schematic diagram illustrating the current LTE/SAE network architecture. The evolving packet core network mainly includes three logic functional entities, namely Mobility Management Entity (MME), Service Gateway (S-GW), and Packet Gateway (P-GW). The MME is configured to store mobile management context of the UE, such as user identity, handle Non-Access Stratum (NAS) signaling and ensure the security of NAS signaling. The S-GW is configured to store user plane context of the UE, such as the IP address and routing information of the UE, and implement lawful interception and packet data routing. The S-GW is communicated with the MME through an S11 interface, which exchanges mobility management information and session control information of the UE. The P-GW is configured to route and forward packets, deliver enhanced charging policy, and filter packets based on each UE. The P-GW is communicated with the S-GW through an S5 interface to transfer control information such as information creation, modification and deletion, and implement packet data routing. The MME is communicated with the E-UTRAN control plane via the S1-MME and the S-GW is communicated with the E-UTRAN network user plane via the S1-U. In addition, the MME is communicated with a 2G/3G access network via an S3 interface to anchor the mobility control plane of the UE between networks. The S-GW is communicated with an SGSN via an S4 interface to anchor the user plane of the UE between networks.
Notably, during the evolution from an old network to a new one, the old and evolving networks will coexist for some time. In order to ensure the compatibility with existing systems, one of 3GPP's objectives in terms of network evolution, mobility management must be accomplished between E-UTRAN and UTRAN, and between two E-UTRANs of the Global System for Mobile (GSM) communication system.
The UE may roam between different areas of the same network. For example, when roaming between Routing Areas (RA) in the existing 2G/3G access network, the UE initiates a Routing Area Update (RAU) process. Obviously, the UE periodically updates its location during RA updating for the network to know that the UE is currently communicated with the network, so as to prevent the UE from being called continuously. While moving within the Tracking Area (TA), the UE initiates a Tracking Area Update (TAU) process. The UE may also roam between different networks. When moving to a new network, the UE registers with the current network. For example, when entering a first RA, the UE registers with the SGSN of the 2G/3G access network. When entering a first TA, the UE registers with the MME of the evolving network. When the UE moves out of the first TA and enters the first RA, it has to again register with the SGSN of the 2G/3G access network. In this way, the UE frequently registers with different networks, causing a considerable amount of registration signaling overhead.
An existing technology, known as Idle-mode Signaling Reduction (ISR) solution, may reduce the impact of registering and updating the UE working in Tunnel Endpoint Identifier (TEID) mode between radio access networks on air interfaces. In this situation, the UE may register with two different radio access networks simultaneously, thus eliminating the need for the UE to launch any registration process while moving between registration areas of these two networks. Specifically, a serving gateway of the access network where the UE is located may carry the information of the access network, with which the UE is registered. Given existing Idle-mode Signaling Reduction, information is processed in this way: When the UE registers with the current access network, the corresponding serving gateway may carry information relating to the current network. When the UE registers with another access network and the serving gateway remains unchanged, the serving gateway may carry information relating to the new access network. Thus, as the serving gateway carries information of the two different access networks, with which the UE is registered, no registration process is launched when the UE moves between registration areas of the two networks.
While researching and practicing the method of information processing given the signaling restriction, the present inventor has noted the following.
Given the signaling restriction, the serving gateway carries information relating to the two access networks, with which the UE is registered. When the UE moves within the corresponding areas of these two access networks, the serving gateway needs to update the information relating to the current access network where the UE is located. In this way, the UE may communicate normally. When updating the current access network where the UE is located, the existing serving gateway often updates the information relating to other access networks, with which the UE is registered, causing the UE to initiate a re-registration process while moving to another network. This adversely affects the UE's communication when the UE moves between access network areas. The issue remains unresolved so far.